Oscillating doctor-blade mechanism

ABSTRACT

Disclosed herein is a fluid actuated device for oscillating a doctor blade specially adapted for paper mills, said device having a pair of inflatable members each having one side secured to a fixed plate and the other side secured to a movable plate supported between the fixed members and a water control system to alternately inflate the inflated members to move the movable plate relative to the fixed plates, the motion of the movable plate being transmitted to the doctor blade to be oscillated. Control is effected by a variable exhaust line restriction and a solenoid valve actuated by a remote pulse forming timer capable of actuating many such devices without modification.

United States Patent 1191 i Wake [4 1 Aug. 7, 1973 OSCILLATING DOCTOR-BLADE 3,255,776 6/1966 Noorlander 137/625.64

MECHANISM 2,318,504 5/1943 2,417,796 3/1947 75] lnventor: Herbert D. Wake, Green Bay, Wis. 2,544,557 3/1951 [73] Assisnec: Essco Inc" Green y Wis 3,128,207 4/1964 Schmrtt ll8/l26 [22] Filed: June 181 1970 Primary Examinerl,eon G. Machlin 2 App] 47,275 An0rneyWheeler, House & Wheeler [63] C t' t S 1 /l 7 :9 566 N [57] ABSTRACT Oll 111118 lOIl-ll'l- 19 8 par 0 er 0 0v Disclosed herem 1s a fluid actuated device for oscillating a doctor blade specially adapted for paper mills, [52] U.S. C1. 15/256.53 said device having a Pair of inflatable members each 51 1111. C1 D2lg 3/00 having side secured a fixed Plate and the 581 Field of Search 15/251353; 34/85, Side Secured Plate PP between the [56] References Cited UNITED STATES PATENTS fixed members and a water control system to alternately inflate the inflated members to move the movable plate relative to the fixed plates, the motion of the movable plate being transmitted to the doctor blade to be oscillated. Control is effected by a variable exhaust line restriction and a solenoid valve actuated by a remote pulse forming timer capable of actuating many 1% 60/551531; such devices without difi ti 2,019,766 11/1935 Peterson .....................IIIIIII: 91/39 9 Claims, 5 Drawing Figures w f" /Z 2a 24 i I 2.5 1 //Z d Z j 15;: //2

v: I. 1 1 -53 K 2/ J 20 RELATED APPLICATION This application is a continuation in part of my copending application Ser. No. 779,566, filed Nov. 27, 1968.

BACKGROUND OF THE INVENTION In the rolling operations, such as printing, drying or calendering paper, the surfaces of the rolls must be continuously wiped to maintain an even distribution of the printing ink or to clean the drying and calendering rolls. Doctor blades are commonly provided to wipe the surfaces of the rolls and are oscillated at a low frequency to increase their efficiency of operation.

Electro-mechanical oscillators are employed where space permits or where ambient temperature or humidity is not beyond the limits of gear-motor application. If an elecric motor is used, the high humidity may cause an electric shock hazard. Oil seals often break down due to the high heat. In any system where lubricants or oils are used, there is always the possibility of the lubricant or oil contaminating the paper on the rolls.

SUMMARY OF THE INVENTION The fluid actuated device disclosed herein provides a controlled low frequency oscillation using components which are not affected by the operating environment and fluidswhich are compatible with the products being manufactured; The oscillating device includes a frequencies and cycles of operation can be obtained with this control system by the proper selection of the cam contour and adjustment of the flow restrictor, including continuous motion, a delay at one end of each stroke of the oscillating device, or a delay in motion at each end of .the stroke of the oscillating device. The rate of motion is controlled by an adjustable flow res'trictor positioned in the exhaust line of the inflatable members to maintain a continuous positive operating pressure in the oscillating device. This ensures that adequate power will be available at the balloon and gives great flexibility of control in combination with the cam in the interval timer. f

Other objects and advantages will become apparent from the fllowing description when read in connection with the accompanying drawings, in which:

FIG. 1 is a top view of the oscillating device shown connected to two doctor blades.

FIG. 2 is an end view of the oscillating device shown in FIG. 1.

FIG. 3 is a top view in section of the oscillating device shown in FIG. 1.

FIG. 4 is a schematic diagram of the fluid pressure system for the oscillating device.

FIG. 5 is a circuit diagram for a timer used to control the operation of a plurality of the oscillating devices.

FIG. 6 is a side view in elevation of amodifed oscillating device using pivotal motion.

FIG. 7 is an end view of the modified oscillating device of FIG. 6.

DESCRIPTION OF THE INVENTION Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

Referring more specifically to the drawings, the oscillating device 10 is shown connected to oscillate a pair of doctor blades 12 positioned to wipe the surface of a pair of rolls 14. The oscillating device 10 includes a pair of inflatable or expandable members 20 and 22 to move a common or movable plate 36 relative to a pair of fixed plates 24 and 26. A single inflatable bag or balloon could be used by storing energy for the return stroke in a spring, or the like, in which case a one-way solenoid valve could be used.

More particularly, the oscillaating device 10 includes a pair of fixed plates 24 and 26 and a movable plate 36 supported by means of a pair of parallel shafts 28 and 30 for axial or linear movement in bearings 32 and 34 provided in each of the plates ,24 and 26, respectively. The movable plate 36 is secured to the shafts 28 and 30 in substantially parallel relation to the fixed plates 24 and 26. The motion of the shafts 28 and 30 is transferred to the doctor blades 12 by links 29 and 31 connected to the shafts 28 and 30, respectively, and to the shafts 33 for the doctor blades. Oscillating motion of the plate 36 between the fixed plates 24 and 26 is produced by meansof the inflatable bag members 20 and 22 which are positioned on each side of the plate 36.

In this last regard, each of the inflatable members 20 and 22 is formed from a resilient material such as rubber in the form of a sleeve or wall 21 and 23 with an annular bead 38 at each end. The resilient sleeve 21 is retained between the movable plate 36 and the fixed plate 24 by means of an apertured disc 40 mounted on the fixed plate 24 and a channeled disc 42 mounted on movable plate 34. The apertured disc 40 is provided with an arcuate groove 44 to engage the bead 38 at one of the sleeve 21 and the channeled disc 42 is provided with an arcuate groove 46 to engage the bead 38 at the other end of the sleeve 21. Similarly, the resilient sleeve 23 is retainedv between the movable plate 36 and the fixed plate 26 by means of an apertured disc 48 mounted on fixed plate 26 and a channeled disc 50 mounted on movable plate 36. The apertured disc 48 is provided with an arcuate groove 52 to engage the bead 38 at one end of the sleeve 23 and the channeled disc 50 is provided with an arcuate groove 54 to engage the bead 38 on the other end of the resilient sleeve 23. The beads 38 are sealed in the arcuate grooves to form fluid tight expandable bags or balloons. Fluid under pressure is alternately admitted to the resilient sleeve 21 and 23 through conduits 56 and 58 connected to inlet openings 60 and 62 provided in the apertured discs 40 and 48, respectively. Although the bags or balloons are shown formedby sleeves having discs secured to each side, it is within the contemplation of the invention to use an inflatable member in the form of a 'balloon to produce motion between the plates.

Means areprovided to control the flow of pressurized fluid such as water to the sleeves 21 and 23 to produce a low frequency oscillation or vibration of the movable plate 36 between the fixed plates 24 and 26. This means includes the solenoid actuated reversing valve 16 and the timer assembly 18. The valve 16 is used to control the flow of fluid from a conventional pressure source such as a pump (not shown) to the oscillating device and back to a reservoir 70. The valve 16 includes a cylindrical housing 64 having a pair of ports 65 and 66 on one side connected to the lines 56 and 58, respectively, and a pair of ports 67 and 68 on the other side respectively connected to a conduit 59 for reservoir 70 and a conduit 61 for the source of pressurized fluid. The flow of fluid through the housing 64 is controlled by means of an axially movable armature 74 having a pair of inlet passages 75 and 76 and a pair of outlet passages 77 and 78. In the initial position of the armature 74 in the housing 64, shown in FIG. 4, the inlet passage 75 will be aligned with ports 66 and 68 and the outlet passage 77 will be aligned with ports 65 and 67. Fluid will then flow to member 22 and exhaust from member 20. When the armature 74 is moved to the right to the reverse flow position, inlet passage 76 will be aligned with ports 68 and 65 and outlet passage 78 will be aligned with ports 66 and 67. Fluid will then flow to member and exhaust from member 22. The armature 74 is biased to the initial position by means of a spring 80 and is moved to the right by means of a solenoid coil 82 energized in a timed sequence by the timer assembly 18.

More particularly, the timer switch assembly 18 controls the operation of the solenoid valve 16 according to a predetermined timed sequence. This assembly 18 includes a housing 84 having a large cam 86 mounted for rotary motion in the housing and driven by means of an electric timer motor 88 connected to the power source L L by leads 87 and 89. A micro-switch 92 is mounted in the housing in close proximity to the cam 86. The micro-switch 92 is intermittently closed by means of a lobe 90 provided on the surface of the cam in a position to engage a switch actuator 91 on the micro-switch 92. Any number of lobes 90 may be provided in desired positions on the cam 86. The switch 92 is connected to the solenoid coil 82 by leads 94 and 96 to energize the coil each time a lobe 90 engages the actuator 91. The time sequence for energizing the coil will depend on the length of the lobe 90 and can be extended to provide an equal or unequal time interval for each position of the armature. The timer assembly 18 can be used to control a number of reversing valves by mounting additional switches 100 around the periphery of the cam 86, driving a number of cams on a common shaft, or by connecting a number of solenoid coils 82 to a single switch 92. If a plurality of oscillators are controlled by the timer switch assembly, the switches can be actuated simultaneously by providing a lobe on the cam for fluid pressure to operate all of the oscillators at one time, the lobes can be staggered to sequentially actuate the switches. An on-off switch 102 is provided in the line L, to control the operation of the timer assembly 18 and an indicator light 104 may be connected to the line L, if desired.

The rate of movement of the movable plate 36 is controlled by means of an adjustable restrictor 110 connected in the return line 59 to the reservoir 70. By controlling the flow of fluid in the exhaust line 59, the pressure of the fluid expanding the member 20 and 22 will always be constant. This assures adequate power for movement of the doctor blades 12 while providing a means for adjusting the rate of motion. Means are provided to adjust the amount of motion of the movable plate 36 relative to the fixed plates 24 and 26 and to prevent complete collapse of one of the members 20 and 22. This is accomplished by means of the adjustment screws 112 received in threaded aperture I14 provided in the movable plates 24 and 26.

The oscillating device 10 can also be varied by holding the movable plate 36 stationary and allowing the fixed plates 24 and 26 to move relative thereto. Also, the doctor blades 12 may be vibrated directly by connecting the resilient members 20 and 22 to each end of the shaft 33 for one of the doctor blades 12. Another alternative would be to mount a single resilient member in combination with a means to bias the vibrating member in the opposite direction such as a spring.

Another embodiment of the oscillating device is shown in FIGS. 6 and 7 and includes a fixed bracket or housing having parallel end walls or plates 122 forming a central cavity 123. A movable plate 124 is supported for pivotal movement within the cavity 123 by means ofa shaft 126 journalled in openings 128 provided in the sidewalls 129 of the housing 120. The plate 124 is fixedly secured to the shaft 126 by a key 125. The oscillating or pivotal motion of the shaft 126 is transferred to a doctor blade by means of a lever arm 134 secured to the shaft 126 by a key 127 with the free end 136 of the arm 134 positioned in a slot 138 provided in a shaft 140 connected to the doctor blade.

Relative movement of the plate 124 with respect to the shaft 126 is produced by means of inflatable or expandable members and 132 in the form of sleeves positioned between the plate 124 and the end walls 122. The sleeves 130 and 132 are similar in construction to the inflatable members 20 and 22 described above. Pivotal movement of the plate 124 about the axis of shaft 126 is produced by alternately pressurizing the inflatable members through conduits 56 and 58, respectively, by means of the solenoid actuated reversing valve 16 and the timer assembly 18, described above. Although the oscillating device of this embodiment has only a single lever arm 134, it should be apparent that a second lever arm can be attached to the other end of shaft 126 to operate a second doctor blade.

Water is the preferred operating fluid for a doctor blade on a machine for manufacturing paper, because it is compatible with the water in the paper. Other fluids could be used by it is preferable that the fluids be compatible with the fluids in the product being manufactured. Air is suitable in many applications.

Although the oscillator has been shown connected to oscillate one or more doctor blades, it should be apparent that it can be used to oscillate other devices.

What is claimed is:

1. In a doctor blade, an oscillating device comprising a fixed plate,

a movable plate,

means supporting said movable plate for relative movement with respect to said fixed plate,

an inflatable member positioned between said fixed plate and said movable plate, and adapted to move said movable plate upon inflation,

means offset from the path of said movable plate adapted to transmit oscillation of said movable plate to said doctor blade,

and means to cause periodic flow of water to said inflatable member including means to initiate said flow at fixed time intervals and means to restrict the rate of motion of said movable plate relative to said fixed plate comprising an exhaust passage from said inflatable member and flow regulating means in said exhaust passage adapted to control the rate of flow away from said inflatable member.

2. A device according to claim 1 wherein said means to initiate said flow includes a cam having a lobe of predetermined length and a switch having an actuator positioned in the path of motion of said lobe.

3. A device according to claim 2 wherein a number of said switches are so positioned, each said switch being adapted to initiate said periodic flow to a said inflatable member.

4. In a doctor blade, an oscillating device comprising a fixed plate,

a movable plate,

means supporting said movable plate for relative movement with respect to said fixed plate,

an inflatable member positioned between said fixed plate and said movable plate,

means to transmit oscillation of said movable plate to said doctor blade,

and means to cause periodic flow of pressurized water to said inflatable member including means to initiate said'flow at'fixed time intervals, said device including a second fixed plate, and a second inflatable member positioned between said second fixed plate and said movable plate,

said means to cause periodic flow of pressurized water including means to alternately inflate said inflatable members,

each said inflatable member having an exhaust passage and a flow regulating means in each said exhaust passage adapted to control the rate of flow away from each said inflatable member,

said means to initiate said flow including a single cam having a lobe of predetermined length and a switch adapted to initiate said flow and having an actuator in the path of said lobe, a said switch being provided for each said inflatable member, each said switch being adapted to occupy a plurality of positions along the path of said lobe.

5. A device according toclaim 4 wherein said supporting means includes a shaft mounted for linear movement in said fixed plates.

6. A device according to claim 4 wherein said supporting means includes a shaft mounted for pivotal movement with respect to said fixed plates.

7. A device according to claim 4 wherein saidmeans to cause periodic flow includes a solenoid actuated reversing valve,

said switch being connected to control said valve.

8. In combination, a doctor blade,

an oscillating device comprising a pair of fixed plates,

a movable plate,

means supporting said movable plate for relative movement with respect to said fixed plates along a path,

means offset from said path and from said fixed plates connecting said movable plate and said doctor blade and adapted to oscillate said doctor blade with said movable plates,

a first inflatable member positioned between said movable plate and one of said fixed plates, a second inflatable member positioned between said movable plate and the other of said fixed plates, means to cause periodic flow of pressurized water to alternately inflate said inflatable members,

said means to alternately inflate said inflatable members including a solenoid actuated reversing valve to control the flow of pressurized water, a switch connected to control said valve, and a cam having a lobe positioned to periodically actuate said switch, and

an exhaust passage from said inflatable members and an adjustable fluid flow restrictor in each of said exhaust passages to restrict the rate of motion of said movable plate relative to said fixed plates.

9. In combination, a doctor blade, and an oscillating device comprising a fixed plate,

a movable plate,

means supporting said movable plate for reciprocating movement relative to said fixed plate,

an inflatablemember positioned between said fixed plate and said movable plate and adapted to move said movable plate upon inflation,

motion transmitting connections between said movable plate and said doctor blade, said connections being offset from the path of said plate,

an exhaust passage from said inflatable member,

means controlling the rate of flow of fluid away from said inflatable member through said passage and means to cause periodic flow of pressurized water to said inflatable member including a cam having a lobe of predetermined length and a switch having an actuator positioned in the path of motion of said lobe. 

1. In a doctor blade, an oscillating device comprising a fixed plate, a movable plate, means supporting said movable plate for relative movement with respect to said fixed plate, an inflatable member positioned between said fixed plate and said movable plate, and adapted to move said movable plate upon inflation, means offset from the path of said movable plate adapted to transmit oscillation of said movable plate to said doctor blade, and means to cause periodic flow of water to said inflatable member including means to initiate said flow at fixed time intervals and means to restrict the rate of motion of said movable plate relative to said fixed plate comprising an exhaust passage from said inflatable member and flow regulating means in said exhaust passage adapted to control the rate of flow away from said inflatable member.
 2. A device according to claim 1 wherein said means to initiate said flow includes a cam having a lobe of predetermined length and a switch having an actuator positioned in the path of motion of said lobe.
 3. A device according to claim 2 wherein a number of said switches are so positioned, each said switch being adapted to initiate said periodic flow to a said inflatable member.
 4. In a doctor blade, an oscillating device comprising a fixed plate, a movable plate, means supporting said movable plate for relative movement with respect to said fixed plate, an inflatable member positioned between said fixed plate and said movable plate, means to transmit oscillation of said movable plaTe to said doctor blade, and means to cause periodic flow of pressurized water to said inflatable member including means to initiate said flow at fixed time intervals, said device including a second fixed plate, and a second inflatable member positioned between said second fixed plate and said movable plate, said means to cause periodic flow of pressurized water including means to alternately inflate said inflatable members, each said inflatable member having an exhaust passage and a flow regulating means in each said exhaust passage adapted to control the rate of flow away from each said inflatable member, said means to initiate said flow including a single cam having a lobe of predetermined length and a switch adapted to initiate said flow and having an actuator in the path of said lobe, a said switch being provided for each said inflatable member, each said switch being adapted to occupy a plurality of positions along the path of said lobe.
 5. A device according to claim 4 wherein said supporting means includes a shaft mounted for linear movement in said fixed plates.
 6. A device according to claim 4 wherein said supporting means includes a shaft mounted for pivotal movement with respect to said fixed plates.
 7. A device according to claim 4 wherein said means to cause periodic flow includes a solenoid actuated reversing valve, said switch being connected to control said valve.
 8. In combination, a doctor blade, an oscillating device comprising a pair of fixed plates, a movable plate, means supporting said movable plate for relative movement with respect to said fixed plates along a path, means offset from said path and from said fixed plates connecting said movable plate and said doctor blade and adapted to oscillate said doctor blade with said movable plates, a first inflatable member positioned between said movable plate and one of said fixed plates, a second inflatable member positioned between said movable plate and the other of said fixed plates, means to cause periodic flow of pressurized water to alternately inflate said inflatable members, said means to alternately inflate said inflatable members including a solenoid actuated reversing valve to control the flow of pressurized water, a switch connected to control said valve, and a cam having a lobe positioned to periodically actuate said switch, and an exhaust passage from said inflatable members and an adjustable fluid flow restrictor in each of said exhaust passages to restrict the rate of motion of said movable plate relative to said fixed plates.
 9. In combination, a doctor blade, and an oscillating device comprising a fixed plate, a movable plate, means supporting said movable plate for reciprocating movement relative to said fixed plate, an inflatable member positioned between said fixed plate and said movable plate and adapted to move said movable plate upon inflation, motion transmitting connections between said movable plate and said doctor blade, said connections being offset from the path of said plate, an exhaust passage from said inflatable member, means controlling the rate of flow of fluid away from said inflatable member through said passage and means to cause periodic flow of pressurized water to said inflatable member including a cam having a lobe of predetermined length and a switch having an actuator positioned in the path of motion of said lobe. 